The Assassination Run(1980)

While attending Oxford University, Mark Fraser is recruited as an agent by Department Six of British Intelligence. In time he becomes one of their top "eliminators." After several years, he resigns in disgust, marries his girlfriend, Jill Marshall, and retires to the Scottish Highlands. While shopping one afternoon, Jill is kidnapped by five German terrorists and brought to Spain. When Mark receives a telephone call from the terrorists, instructing him to assassinate a right-wing German publisher, he is forced to employ his old skills as a hit man to ensure Jill's safety. .